martinfry, Have you tried rolling your foot over a frozen bottle of water? This helped mine. Have you tried massaging your feet/foot with Voltaren Gel? This also helped mine. Buying good supportive shoes and losing weight helped me.

I did it all. Injections, Pulling the big toe back gently, other stretches, splints, boot, socks, etc., to no avail. The above mentioned helped the most. Strangely, when I get my arthritic needs injected, the cortisone shot is systemic and stops my feet from hurting if they are flared up.

I do not recommend injections in the heel because it can do more harm than good in the long haul....look this up. My podiatrist & orthopedic doctor did not recommend that approach either. You have to be injected from the side and with the site up on a screen so they know where to inject the cortisone. NEVER straight up in the heel......OUCH! I made the mistake of doing that with another doctor years ago when my PF first started....3 months later, I was in pain again and had risked the chance of more damage due to the way the injection was done.

Praying for you. It is so painful and I empathize. Blessings....